Compressors are often utilized in a myriad of applications and industrial processes to compress one or more process fluids (e.g., gases). Conventional compressors may often include a casing or cylinder having one or more valve assemblies (e.g., check valve assembly) configured to handle large volumes of the process fluids directed to and/or discharged from the compressor. The cylinder of the conventional compressors may often define one or more openings or bores and the valve assemblies may be disposed in the bores to handle the process fluids flowing therethrough. In operation, the process fluids contained in the cylinder of the compressors are often pressurized to relatively high pressures. Accordingly, the bores of the cylinders may typically include closure devices or covers configured to seal the bores to prevent leakage of the pressurized process fluids from the cylinder to the surrounding atmosphere. In addition to sealing the bores, the covers may also be configured to retain the valve assemblies within the bores of the compressors.
As advancements are made in the industrial processes, however, production requirements for the conventional compressors are often heightened. In many cases, to meet the heightened production requirements, the process fluids may be pressurized to relatively higher pressures. The higher pressures of the process fluids in the compressors may subsequently expose the cylinder and the covers sealing the bores and/or retaining the valve assemblies disposed therein to increased pressures. The covers in conventional compressors, however, may not be capable of sufficiently sealing the bores and/or retaining the valve assemblies disposed therein, thereby resulting in leakage of the process fluid from the cylinder to the surrounding atmosphere via the bores and/or the valve assemblies. Further, the covers in conventional compressors may not provide a means to monitor the leakage of the process fluids from the cylinders, which may present a hazardous and/or fatal environment for nearby operators. For example, the process fluids may often contain one or more hazardous gases (e.g., hydrogen sulfide), which have been proven to be fatal in quantities as small as 20 parts per million (ppm). In another example, the leaked process fluids may contain one or more volatile hydrocarbons, which may combine with the surrounding atmosphere in stoichiometric mixtures to provide a potentially explosive environment.
What is needed, then, are improved covers and methods for sealing bores defined in a cylinder of a compressor and/or retaining valve assemblies disposed in the bores that are capable of monitoring leakage of process fluids from the cylinder of the compressor.